1. Technical Field
The present invention relates to a piezoelectric motor, a driving device, an electronic component conveying device, an electronic component inspection device, a printing device, a robot hand, and a robot.
2. Related Art
A piezoelectric motor which vibrates a member (vibrating body) formed of a piezoelectric material to drive an object is known. The piezoelectric motor can have a small size compared to an electromagnetic motor which rotates a rotor by an electromagnetic force, can obtain a large driving force, and can align the object with high precision. For this reason, the piezoelectric motor is used as an actuator for various devices, such as a driving mechanism of a camera.
The piezoelectric motor operates under the following principle. First, a vibrating body is formed to have a substantially rectangular parallelepiped shape, and has a convex portion protruding from an end surface in a longitudinal direction. If a voltage with a predetermined frequency is applied to the vibrating body, vibration in which the vibrating body is stretched and vibration in which the vibrating body is bent are simultaneously generated. When this happens, the end surface of the vibrating body starts an elliptical motion to rotate in one direction. Accordingly, if the convex portion provided at the end surface is pressed against the object, the object can be moved in a given direction with a frictional force acting between the convex portion and the object.
Under this operation principle, the piezoelectric motor is used in a state where the convex portion provided at the end surface of the vibrating body is pressed against the object. It is also necessary to retain the vibrating body such that the vibrating body does not escape or dislodge due to a reaction force received by the convex portion from the object when driving the object. Nevertheless, the vibration of the vibrating body should be permitted such that the convex portion performs an elliptical motion. Accordingly, a technique in which the vibrating body is housed in a retention case in a state where the convex portion protrudes, both sides of the vibrating body are supported from a bending direction by elastic members in the retention case, and the retention case is pressed against the object along with the vibrating body has been suggested.
JP-A-11-346486 is an example of the related art.
In recent years, however, there is an increasing demand for a reduction in the size and an improvement in the performance of a device having a piezoelectric motor mounted therein. Accordingly, in regard to the piezoelectric motor, there is demand for further reduction in size and improvement in driving precision.
There is a problem that it is difficult to efficiently use energy generated by the vibrating body so as to drive the object. This is because both sides of the vibrating body are supported from the bending direction, such that the vibration of the vibrating body is easily transmitted to the outside through the retention case, and the vibration transmitted to the outside cannot be used to drive the object.